Fendalton bus boarders

Once in a while, we get asked about the science behind the mini bus boarders in Christchurch's Fendalton Road. Traditionally, buses stop in bus bays. In some locations, there are inline bus stops, where buses stop at a straight kerb line. The handful of bus stops on Fendalton Road that have such in-lane stops have an unusual kerb extension of about 300 mm. How come?

Axel Downard-Wilke was asked to develop the scheme design for Fendalton Road's four-laning in about 2001. It was a challenging project that the city council had tried to deliver since 1945 when the adjacent "Burwood Road" was widened as a memorial to fallen airmen; that road has since been renamed Memorial Avenue. The constraint with Fendalton Road has always been the narrow cross section left by the mature trees along the corridors. Hence, Axel's scheme design minimised the carriageway width and parking was to be added last where it did not impact on the existing trees. But what about bus bays, as they would be longer than the space available in between many of those trees?

Bus bays were the most common bus stop layout at that time. Axel ran the idea of having in-lane bus stops past some of his colleagues, and the argument of that causing a lot of rear-end crashes came up quite readily. Red Bus was still the dominant bus operator at that point, and we knew that every time a bus had to go through their maintenance workshop, they logged the reason for it in a database. We asked them about rear end crashes, as there were already some in-lane bus stops around at that time, albeit on less-busy roads. They let us have their database and there were lots of rear end crashes, but none of them at in-lane bus stops, and lots of them at bus bays. Why is that, we wondered?

The answer was found in the behaviour of drivers of both buses and cars. During peak times, bus drivers can wait a long time before somebody is kind enough to let them rejoin the traffic stream (more enlightened countries give public transport indicating after stopping the right of way, but that's another story). Bus drivers have figured out that they can increase the chances of car drivers letting them back in when they half-block the traffic lane. They deliberately drive into the bus bay on an angle (also making it pretty hard for less agile folk to step off the bus onto the carriageway before they then have to mount the footpath). But it certainly has the desired effect and the buses get let back into the traffic stream much more quickly. Sometimes though, a car driver misjudges the remaining gap that is insufficient to overtake, and there is a rear end crash. We found heaps of those in the Red Bus database.

The standard cross section for Fendalton Road saw 8.0 m between kerbs, accommodating two traffic lanes and a cycle lane as shown in the graphic below. At an inline bus stop, we wanted to minimise the risk of ambiguity when a bus is stopped. And that is where the little kerb extensions of 300 mm come into play. Depending on how close the bus is to the kerb, the remaining width to the lane marking between the traffic lanes is about 1.5 m. That's clearly not enough for a driver to sneak past a bus (i.e. no ambiguity) without straddling the adjacent lane, but it's wide enough for a person on a bike to overtake.

We ran this concept past the Automobile Association, the Land Transport Safety Authority (LTSA; they have long since been part of the NZ Transport Agency), the Taxi Federation, and Red Bus. They were all happy and convinced that such a layout would reduce the rear end crashes that one gets at bus bays. The only group that had an issue with the design was Spokes, formerly the Canterbury Cyclists' Association. Upon their request, the city council built bypasses that go behind the bus stop furniture; there is thus a short length of shared path at the bus stops. We doubt, though, that many people on bikes getting caught behind a stopped bus will pass it on the left; the vast majority probably opt for the gap on the right.

But either way, the mini bus boarders in Fendalton Road seem to be working just fine.